Remember too at feed stores you're also at the mercy of the people caring for the chicks. If they have chickens just hope they're practicing bio-security.
One thing I'd add to this in re to adding chickens. I'm pretty fussy about bio-security so will not add adult birds. In fact, I only add chicks and, as a rule, only from the same hatchery. If, as I'm doing this year, I get chicks from another source I isolate them until they are 2 or 3 months...
My second shot at keeping chickens started 30 years ago (I kept them back In HS). My original plan was to keep a couple dozen layers for 3 years,then sell them and get new ones. Did that twice but missed not having them around while new ones came up—missed the roosters too. So I started...